Quick answers
- Does Grant B. Neifeld accept Medicare assignment?
- Yes. Medicare's clinician data says Grant B. Neifeld accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- What is Grant B. Neifeld's NPI number?
- 1215900683. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where Grant B. Neifeld is enrolled with Medicare (CMS data updated October 2, 2026).
- 400 Craven RdSan Marcos, CA 92078 (619) 528‑5000
- 4647 Zion AveSan Diego, CA 92120 (619) 528‑5000
Group practices
Medicare enrollment lists Grant B. Neifeld as a member of this group (CMS data updated October 2, 2026).
- Southern California Permanente Medical Group11,293 clinicians in the group
Specialties
- Family Practiceprimary
Other family doctors in San Marcos
Clinicians with the same Medicare primary specialty in San Marcos, CA — not a recommendation.
Other clinicians in Southern California Permanente Medical Group
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1976 (50 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1215900683 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians